模拟酸雨胁迫下钙对龙眼光合功能的调节作用

Regulation function of calcium on photosynthesis of Dimocarpus longana Lour. cv. wulongling under simulated acid rain stress.

以福建省主栽品种乌龙岭龙眼为材料研究了模拟酸雨胁迫下钙对龙眼光合功能的调节作用 .结果表明 ,叶绿体的反应介质中Ca2 + 浓度在 0～ 5mmol·L-1范围内可增加其光还原活性 ,以 3 .5mmol·L-1的活性最高 ,比对照增加 41.90 % ;而 2mmol·L-1EGTA会使其活性下降 2 6 .0 6 % ;Mn2 + 和Mg2 + 对光还原活性均有抑制作用 .0～ 6mmol·L-1的Ca2 + 可提高叶绿体的光合磷酸化活性 ,最适的浓度为 4.5mmol·L-1;0～ 8mmol·L-1的Ca2 + 可提高叶绿体超氧物歧化酶 (SOD)活性 ,最适浓度为 6mmol·L-1.pH 3 .0的酸雨胁迫下 ,10mmol·L-1和 15mmol·L-1Ca(NO3) 2 均可减缓叶绿素的降解 ,稳定叶圆片的膜结构 ,降低膜透性 ,以 15mmol·L-1的效果较佳 ;Ca(NO3) 2 浓度超过 2 0mmol·L-1加剧了酸雨对叶片的伤害作用 .喷15mmol·L-1Ca(NO3) 2 可增加叶片光合速率 ,表现出模拟酸雨胁迫下钙对龙眼叶片的良好保护作用 .

Studies on the regulation function of calcium on photosynthesis of Dimocarpus longana under simulated acid rain stress showed that the photoreduction activity of chloroplasts was activated when the concentration of calcium ion in reaction medium ranged from 0 to 5 mmol·L -1 ,and peaked at the 3.5 mmol·L -1 , which was 41.90% higher than that of control. Conversely,the activity of chloroplasts reduced 26.06% in the reaction medium with a concentration of 2 mmol·L -1 EGTA,as compared with the control. Both Mn 2+ and Mg 2+ could inhibit photoreduction activity. The photophosphorylation activity increased when the concentration of calcium ion in reaction medium ranged from 0 to 6 mmol·L -1 ,and peaked at the 4.5 mmol·L -1 ,while superoxidase dismutase (SOD) activity rose from 0 to 6 mmol·L -1 and peaked at 6 mmol·L -1 . Calcium ion with the concentration of both 10 mmol·L -1 and 15 mmol·L -1 could increase the content of chlorophyll(Chl),stabilize the membrane structure of leaf discs,and reduce the membrane permeability under simulated acid rain with pH value of 3.0. The effect in 15 mmol·L -1 were better than in 10 mmol·L -1 . However,the injury of acid rain to leaves was strengthened when the concentration of calcium was higher than 20 mmol·L -1 . Net photosynthesis rate (Pn) rose when leaves sprayed with 15 mmol·L -1 Ca(NO 3) 2 before treatment of acid rain stress of pH 2.5. All of the results represented the excellent protection function of calcium on D.longana leaves under simulated acid rain.